1. Field of the Invention
This invention relates to a system for remotely verifying the presence of a person at a particular location. More specifically, the invention relates to improvements in a remote monitoring system of the type disclosed in U.S. Pat. No. 5,537,102 (hereinafter, the EMS patent), and in particular to a remote monitoring system and method that adds a miniature RF transmitter and home monitoring unit to the tamper proof electronic device disclosed in the EMS patent. In addition, the invention relates to a system for simplifying installation of a home monitoring unit, and to a system which reduces offender monitoring costs by employing an inexpensive Internet connection between a home monitoring unit and a central monitoring station.
2. Discussion of Related Art
The device disclosed in the EMS patent, a commercial version of which is currently being offered by Electronic Monitoring Systems, Inc., is a tamper proof electronic device that is worn like a wrist watch. The currently preferred embodiment of the device described in the EMS patent, which is hereby incorporated by reference, includes a sound generator capable of emitting acoustic tones and of prompting the person wearing the device with an audible alarm, either at pre-scheduled times or at seemingly random intervals, to call a central monitoring station and establish his or her identity by holding the device to the telephone and causing the device to emit a coded sequence of tones, for transmission over the telephone line to the central monitoring station. Location of the caller is established by Caller I.D. or Automatic Number Identification (ANI).
Tampering with the wrist device is prevented by a fiber optic circuit in the wrist band, while duplication or simulation of the coded sequence of tones is prevented by changing the sequence in a pseudorandom manner, as defined in the EMS patent, at regular or pseudorandom intervals.
The device thus provides a secure way to positively track a person at any location with access to a telephone, and is therefore suitable for a variety of tracking applications including monitoring of individual offenders in court-ordered house arrest or work-release programs.
Despite the advantages of providing a self-contained monitoring unit that permits random tracking of an individual to any location with a telephone, and optionally to other locations by means of a cellular or satellite location determining system, the system disclosed in the EMS patent has a few disadvantages. In particular, if the person being monitored fails to initiate contact either at scheduled or random intervals, that person may use the excuse that he or she slept through the alarm or a wake-up call, or was otherwise occupied in such a way that the telephone could not be reached in time to initiate the required telephone call, even though the individual might actually have simply been away from the scheduled location. In addition, some jurisdictions require that an individual being monitored be permitted a certain amount of sleep at night, during which time the individual cannot be disturbed, either by the alarm or by providing wake-up calls.
One solution to the problem of non-compliance with call-in requests in situations where tampering has not occurred is to use a monitoring system of the type in which the monitored person wears a radio frequency (RF) transmitter that communicates with a monitoring unit connected to the monitored person's home telephone and is arranged to call in status reports without intervention. In theory, such monitoring systems provide for continuous monitoring of a monitored person during periods when the monitored person is required to be at home. Examples of this type of arrangement are disclosed in numerous U.S. patents, including U.S. Pat. Nos. 3,478,344, 4,598,272, 4,812,823, 4,952,913, 4,973,944, 4,980,671, 4,999,613, 5,032,823, 5,189,395, and 5,627,520, and others, and versions thereof are currently being offered by a number of companies.
Obviously, such systems have the disadvantage of not being able to provide random tracking, and it was in fact a specific objective of the system described in the EMS patent to overcome the disadvantage of RF transmitter-based systems by avoiding their use entirely. In addition, however, such systems have proven unreliable in practice, tending to generate false alarms. To avoid having to respond to isolated alerts, companies employing RF transmitter systems will not report an offender as having left his home until, for example, five to twenty coded signals in a row over the course of five to twenty minutes have not been received. Even using this strategy, there are a number of instances where the offender is really at home yet the radio transmitted signals were not received. To resolve instances such as this, the offender is often called from the central monitoring station and asked to identify himself by stating his birthday or social security number. This is clearly a marginal solution. In other instances, the central station may use voice identification to attempt to identify an offender. This is a better but still marginal method that is open to fraud. In contrast, the use of coded acoustic tones as described in the EMS patent provides a 100% reliable method for determining if the offender is present.
Not only do such systems have the disadvantages of limited tracking area and a high incidence of false alarms in comparison with the EMS system, but installation of the hardware required to implement an RF transmitter based monitoring system is relatively difficult, usually requiring an officer to enter the monitored person's home in order to establish the necessary connections, and the conventional stationary installation requires a relatively expensive direct telephone connection to the central monitoring station, usually by means of a toll-free number paid for by the monitoring service.
In spite of these problems with conventional continuous monitoring arrangements, the present invention now proposes to combine the wrist device described in the EMS patent, which can be used independently of any home monitoring unit and provides 100% reliability, with a miniature RF transmitter system, thereby obtaining a device which offers the reliability and random tracking advantages of the device described in the EMS patent, as well as the ability to monitor an individual at times while the individual is supposed to be sleeping or is otherwise indisposed.
While the lack of random tracking capabilities of RF transmitter systems has previously been recognized, the conventional approach has been to add call-in features in which identification of the caller is made based on words spoken by the caller, or on some type of voice identification software. An example of an arrangement which includes voice identification capabilities is found in U.S. Pat. No. 5,023,901, but because of the low fidelity of a voice transmitted over a telephone system, voice identification is not consistently reliable.
Instead of taking the voice recognition approach, the present invention adds a conventional RF transmitter to the tone-based wrist device described in the EMS patent to periodically send a coded signal to a radio receiver located in the home monitoring unit attached to the telephone line and electrical power in the monitored person's home. In this arrangement, as is conventional, the home monitoring unit's operation is controlled by a microprocessor that is instructed to automatically place a telephone call to a central monitoring station whenever a reportable event, such as a band tamper or failure to return at curfew time, is detected, and to periodically report to the central station to confirm that it is still connected to the telephone line and electrical power, and that no reportable event has occurred.
While this may seem to be a simple combination, however, it has never been attempted or previously proposed. One reason may be that the use of a stationary home monitoring installation directly obviates one of the advantages of the EMS system, namely the advantage of eliminating unnecessary hardware. Nevertheless, properly implemented, this disadvantage can be minimized and is far outweighed by the blanket coverage provided by the combined system of the invention. For example, the present invention provides for cost reduction both with respect to installation and during monitoring, helping to make the proposed combination practicable.
The latter advantage has to do with the fact that, while the transmission of periodic reports confirming connection of the home monitoring unit to the monitored person's home telephone line are essential to ensure that the unit will be able to report any violations, it has been found through practical experience that routine reports from the home monitoring unit to the central monitoring station need not be made in real time, and that even violation reports could, in some instances, be made with a short time delay. As a result, the present invention proposes to use an inexpensive Internet connection for most routine reports as well as some exception reports, while reserving a direct dedicated telephone connection only for certain exception reporting or other specific tasks, such as locating the home monitoring unit by caller I.D. during the setup process and for subsequent periodic checks.
In addition, the present invention addresses the problem of set-up by including a speech synthesizer to facilitate installation of the home monitoring unit. While it has previously been proposed to provide for voice prompting to guide a monitored person through a specific reporting task, the previously proposed systems all provide for the instructions to be transmitted over the airwaves or telephone network, and could not be utilized until the monitoring equipment is installed, rendering them useless for installation.